Refurbishing wooden parallel clamps

I was given a half dozen Jorgenson Wooden parallel clamps that were made in the early 50-60’s. they have been sitting in a garage for all that time and the threads are rusty. I want to refurbish them but can’t figure out how to get the clamps apart so I can clean up the parts. I have been using them even though they are rusty but they don’t open and close as smoothly as they would if the threads were all cleaned up. Any suggestions would be appreciated.

I wouldn’t try to take them apart – i think the fixture the acme threads screw into are a press fit into the maple legs. I would close them up and run the threads against a wire wheel on the grinder, then open them up and get the rest of the threads, just being careful not to touch the wood to the wheel. Give them a light coating of 3 in 1 oil afterward. You can clean and polish the wood with 0000 steel wool and a little WD40 or linseed oil and they’ll clean up really pretty. If you don’t have a grinder you can use a small wire wheel in a drill.

I have made some of these. They worked well but today you can buy the Chinese knock offs that are as good for less money. Watch for them on sale and buy them. I used a 3/8 thread. the acme tap and rod was too costly. I cut and welded the threaded rods. Part is left hand thread and part is right hand. I used file handles. most of the wood was oak from old pallets. I got the plan from some magazine in …..circa 1980. Still think you can buy them cheaper. the tapped rods were donated by a friend. I drilled and tapped I guess he donated the rods and even cut them. They screw together by starting with the long end then the short end is threaded on and then the handles are put on. We drilled the handles and threaded rods and drove in a 1/8 inch dia by 1 inch long roll pin. We bought the threaded rods, roll pins, LH tap and file handles from MCS machine supply. I buy them today. If you really want to make them that is where I could get the best prices at the time. I would like to say the plan was in a Workbench magazine in 1980 to maybe 1982.